Might need a carb - mild upgrade for autocross?

[thatmacguy]

EDIT: I had my bug out today and it feels to me like the bleedin' carb is flaking out on me again. It's been rebuilt 3 times in the last 10 years and every time I get about 2 years out of it, then another year of problems before I break down and get it rebuilt again. I know, I know, the parts are cheap and I should do it myself, but I no longer really have time and so I've just been having it done for me.

So I'm thinking of just replacing the carb, and if I do so I might go with a performance upgrade if advisable. I notice that there are still new Weber 2bbl kits available at a reasonable price, as well as a handful of dual-carb kits, for the 1600 single-port. To me, a 2bbl kit sounds like a great idea - you only use the extra gas when needed. I've had numerous GM products with 4bbl and 2bbl carbs which worked great, but I've heard they can be difficult on Vdubs and that I might be better-off with dual carbs.

Anyone here running a 2bbl or dual-carb setup on a single-port? Worth it? What drivability issues would I see? (daily-drivability remains very important to me.)

What are your opinions on this matter?

Thanks!

Parts are on order and service scheduled to bring me to completion in time for the first Furrin autocross of the season. I'm keeping my fingers crossed!

[gfreel01]

I run dual carbs but I am running a 1835. I had them on the 1600 but it ran to rich. Lean is mean when it comes to racing. To much carb is bad fir the motor.

[VDub63 ( Steven )]

Ask AJ He is great with carbs.

[bren]

If you are interested in the weber progressive 2 barrel talk to Ron Easton. I am pretty sure he runs one in this car:

[vw1s]

I would run duals before a progressive if choosing between them. duals place the carb on a short manifold, almost directly above the head, on purpose built manifolds.

VW designed the stock intake and carb to be a governer of sorts, allowing a driver to run at nearly full throttle on the freeway without over revving and still getting good mileage.
With a progressive you are using what is essentialy a stock intake system, with a bigger carb. The long intake runners lead to fuel fallout and condensation so you end up having to run rich at the carb to get enough atomized fuel to the head, all being limited by the stock diameter intake runners and ends.
My .02

[dubfreak1]

Patrick has this one nailed.

My .02 too

[bren]

Are there good dual carb set ups for single port heads? I have never had a single port so I have not looked into it.

[VDub63 ( Steven )]

Yes Bren, there are single port dual carb set ups.

[thatmacguy]

Thanks guys. I'm finding this board MUCH more useful than the larger ones like Samba. Usually when you ask a question at one of the larger boards you get so many different answers that you just confuse the issue further. I actually get good info here.

As it turns out, my carb may not be at fault as much as my previous distributor, which I have now replaced. I've got another thread about that somewhere here. I may go to a little dual-carb setup next season though. Aircooled.net has a set specific to the single-port, and John and aircooled really seems to know his stuff.

[vw1s]

Apr 24, 2009 11:21:34 GMT -5 thatmacguy said:

...I may go to a little dual-carb setup next season though...

The FV guys used 28PCI's (maybe they still do, Rudy?) They have replaceable venturies, and can be "opened up" using paper thin venturies, and they can be tuned quite easily. I believe there is a little info in the "How to Hot Rod VW's" book about them. A pair of manifolds for single port, duals, would be easy to make with two pieces of pipe and 4 flanges, and a good welder of course. It just so happens...I have 2 pair of 28PCI carbs, one on manifolds for a 40HP! I'm not really looking to sell any of them, they look cool on the shelf! But, if you really want to do this, we may be able to work out an experimental trial type of thing with a pair. I've always wanted to play around with them, but never had the car to do it on. I can make a pair of manifolds, take about 1/2 hour. We can talk more at the show if you'll be there.

[vwcurt]

iv'e had really good luck with a couple (1 at a time) of holley bugspray's. it was developed with VW's in mind. use an isolated tube manifold & 009.

curt